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Written by a former National Geographic employee who also proudly served in Iraq and Afghanistan.

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Tuesday, July 17, 2012

Tree Ring Study Shows Overall Cooling Trend, Recent Temperature Spike

According to a new study by German scientists (in fact they are Geographers), an examination of tree rings has shown that the Roman and pre-Roman periods of Europe were actually warmer than the Medieval Warm Period. The study shows how from 138 BC up to the 1900s experienced a very notable cooling trend. This trend has, at least for now, been stopped by recent warming trends.

The wild, overall cooling trend of temperature. Image from Institute of Geography, JGU

The tree rings challenge all sides of the global warming/climate change debate. The rings show yet again that there is a warming trend. However, it shows that the past was warmer and that climate change occurred naturally. Yet again all scientists must wonder what temperature setting, if any, is optimal, and what forces are at work influencing climate change in all regards. With any hopes this will help silence alarmists who only cloud the climate change debate.

4 comments:

It is possible that the warmer period remembered in human history had been the X-XI Century.In Europe there were vineyards even in southern Scandinavia and the gratest island in the world received the name of "Greenland" because of the prevalent colour.

The first thing that comes to mind is the fact that a record of summer temperatures derived from several trees in Northern Lapland do not represent annual European temperatures and definitely not global temperatures.

The study conjectures that the cooling effect at higher latitudes may also be valid globally, and should be added as a negative forcing in the next IPCC results. This is not tested nor confirmed by this study, and does not match records from other proxies. And actually, it seems highly unlikely as lower latitudes are less sensitive to the solar effects they describe.

Thus, "The tree rings challenge all sides of the global warming/climate change debate", is a definite misrepresentation of the study results and the press release.

The rest of the last paragraph is also your personal opinion, which is not supported in any way by the study results.

But I should add that in this specific case several authors of this study do not agree with the formulation of the press-release, and they suspect that Esper's quotes were taken out of context.

The biggest break through with this study is the fact that they managed to do a reconstruction of tree-ring proxy data where there is no divergence problem between tree-ring and recorded temperature data for last few decades. Not that the current warming is, for some reason, not exceptional.